Currently, burning fossil fuels is the main source of energy
here and around the world.  Those fuels
emitting greenhouse gasses are considered by most associated scientific
organizations in the world as contributing to a potential global catastrophe in
the making.  With this, we are critically
dependent on electricity for almost every necessity we have in our standard of
living. 

A very important concept in electricity production is the
term baseload.  This term is often used
when concluding the need for nuclear energy to be in the mix of clean
electricity sources for modern society. 
Baseload electricity is simply the minimum total electricity used
throughout the year at any given time and region.  This means that all sources combined, the baseload
amount of electricity needs to be supplied continually as the very
minimum.  At different times of the year
and throughout each day, only more electricity than that baseload minimum will
be needed.  So more capacity is required
to meet the day to day variations in peaks and lulls from society demands on
the electrical energy grid.

Familiar renewable energy sources such as wind and solar
panels are not able to contribute to baseload energy needs without some form of
energy storage.  Without reliable storage
capabilities having low conversion loss, these solar based sources would not be
able to start contributing to the baseload. 
This would be based on average solar availability although industrial
scale storage systems do not currently exist, some are in development and do show
promise.

Another common difficulty with wind and solar panel energy
sources is the large area typically required to be committed for the energy
generation capabilities.  This means that
to a first approximation, the energy which can be generated from 100,000 acres
of land devoted to wind turbines and solar panels could be generated by a
fossil or nuclear powerplant on only 100 acres of land.  Specific examples will vary substantially but
if an environmentally friendly option requires not taking up vast sections of
land, then wind and solar panels might have to be concluded as not actually
being environmentally friendly.

Common baseload energy sources are fossil fuels, coal,
natural gas and oil.  In limited
locations, building damns in rivers or drilling for geothermal heat sources can
also provide a contribution to baseload energy supplies.  Burning biomass or growing other organic
material as an energy source are other developing technologies which could
contribute to baseload.

As consumers we all tend to also be interested in which one
will cost me less in my monthly utility bill, currently this latter answer is
burning natural gas as a baseload supplier. 
This does not produce multiple trainloads of ash waste as does burning
coal but it still does emit greenhouse gases.

One often overlooked aspect of energy production is the
amount of energy required to install the power generation capacity per total
amount of energy eventually produced by that installed capacity.  If this is to be considered in grading
environmentally friendly electricity production, then a look at how the various
sources stack up may be worthwhile. 

Which energy source has the lowest overall greenhouse
generation per Watt created in its lifetime? The answer to this select question
appears to be nuclear power, an enormous amount of electricity is produced in a
small area with a single power plant with very little waste generation per
amount of electricity produced. 
Hydroelectric also compares quite favorably behind nuclear in this
regard.  Still if the grading criteria is
shortened simply to consumer cost per Watt and energy produced per total
life cycle energy installation and removal, the two winners would be nuclear and
hydroelectric power supplies (the larger the scale the better).

To those who are convinced all radiation is evil, the main
detractor for nuclear power seems to be the issue of nuclear waste.  True, like all power sources there is some
waste and like so many other things, it needs to be handled safely and disposed
of properly for the entire cycle to meet consensus based standards. 

It might be a red herring to point out that some coal has
sufficiently large quantities of naturally occurring radioactivity that when
burning this coal to make electricity, there is more radioactivity per Watt
generated in the waste of those rare forms of coal than that created by a
nuclear power plant.  More to the point, "safety
is as safety does", if you do something safely then by definition it is
safe.  In other words, everything
involves some form of risk, it is incumbent upon us to manage those risks
accordingly.

The true bottom line is that when it comes to making
electricity, there is no such utopia where this can be done without some impact
to the environment and no waste generation. 
Everything we do generates some waste and has some cost and it really
just comes down to a cost benefit analysis. 
What costs are you willing to pay and for what benefits?